1. Field of the Invention
The present invention relates to process and apparatus for manufacturing a package of a soft sheet for packaging a content such as dry tissues, wet tissues, wipes, sanitary napkins, granular articles, foods or the like or even liquids.
2. Related Art
The package of the soft sheet is generally exemplified by a lengthwise pillow type. FIG. 11 is a perspective view showing the lengthwise pillow type package of the prior art for packaging wet tissues.
A process for manufacturing the package shown in FIG. 11 includes: the step of jointing the edge portions of packaging materials (1) of a soft sheet having laminated aluminum foils and resin films in a joining state to form a longitudinal sealing portion in a cylindrical shape; and the step of sealing the two longitudinal end portions of the cylindrical packaging material (1) to form side sealing portions (2) and (3). Generally, with one side sealing portion (2) being formed, the packaging material (1) is charged with a content from the other opening, and this opening is closed to form the side sealing portion (3).
At a step before forming the longitudinal sealing portion, on the other hand, an opening (4) is formed in a portion of the packaging material (1). At either step, on the other hand, a cover sheet (6) for closing the opening (4) is adhered through such an adhesive layer (or sticking layer) as can be repeatedly peeled and adhered.
The package, as shown in FIG. 11, can be continuously manufactured by the aforementioned lengthwise pillow type manufacture process and apparatus. In the completed package, however, the so-called xe2x80x9cgusset foldsxe2x80x9d (7, 7) are formed on the two sides of the side sealing portions (2) and (3) so that the height size of the package becomes so gradually thinner at the gusset folds (7, 7) as to merge into the side sealing portions (2) and (3). When a cubic content such as stacked wet tissues is packaged, therefore, it cannot be accommodated in a portion of a size L containing the gusset folds (7, 7). This makes the entire volume of the package larger than the content volume. In the longitudinal direction of the package, moreover, the side sealing portions (2) and (3) protrude to enlarge the outer size of the package more.
As a result, there arises a problem that when a small-sized package for packaging a stack of small-folded wet tissues (5) is to be formed, the size of the entire package cannot be sufficiently reduced.
In the prior art, on the other hand, a variety of packaging materials are used to manufacture a box-shaped package. If the package for packaging the content is formed into the box shape, no wasteful space is left in the package, and the large projections such as the side sealing portions (2) and (3) can be eliminated.
According to a general process for manufacturing the box-shaped package of that kind, a hard PET resin sheet is vacuum- or pressure-formed. However, this vacuum- or pressure-forming method requires a forming step using a mold so that it raises the cost. In order to change the size of the package, on the other hand, the mold has to be remade so that a large change cannot be followed. Since the emptied package is hard, moreover, it increases the volume of waste when disposed.
In the food packaging field, on the other hand, there exists a package which is formed from paper into a box shape. However, this paper package has its strength lost when charged with a wet content.
According to an aspect of the invention, there is provided a process for manufacturing a package including a box body formed of a packaging material of a soft sheet and a cover member for closing the opening of the box body, comprising:
(a) the step of forming a box body including a rectangular bottom face portion (12) and four side face portions (13, 14) folded from the four sides of the bottom face portion, of a packaging material of a soft sheet having a monolayer of a resin film or a multi-layer structure having a resin film, to form triangular folded projecting portions (21) projecting outward of the box body at corner portions (20) between first and second side face portions (13, 14) adjoining to each other;
(b) the step of jointing the inner faces of the folded projecting portions (21) along the corner portions (20) and while leaving a predetermined size (W1) from the upper ends of the side face portions (13, 14), to form corner sealing portions (15);
(c) the step of jointing, before or after the step (b) or simultaneously with the step (b), the inner faces of the folded projecting portions (21) in the upper portions of the folded projecting portions (21) and while leaving non-jointed portions of triangular regions (25) using the corner portions (20) as their one side, to form jointed sealing portions (24);
(d) the step of folding the upper portions of the side face portions (13, 14) outward with a predetermined width size (W1) to form first and second flange portions (16, 17) continuing to the upper ends of the first and second side face portions (13, 14), respectively, and simultaneously developing the triangular regions (25) to form flange jointing portions (18) continuing planarly to the individual first and second flange portions (16, 17); and
(e) the step of jointing a cover member (30) to the upper faces of the flange portions (16, 17) and the flange jointing portions (18) developed planarly at the step (d).
The package manufacturing process is preferred to further comprise: the step of cutting, simultaneously with or after the step (b) or the step (c), the folded projecting portions (21) to leave narrow portions (22) including the corner sealing portions (15) and small triangular portions (23) along the jointed sealing portions (24).
The cutting step leaving the narrow portions and the small triangular portions is effective when the box body of the package to be manufactured is deep. In the box body having a large depth and high side face portions, the folded projecting portions (21) have a large projection size. By cutting these folded projecting portions (21) into the aforementioned shape, therefore, the size of the sideway projecting portions from the corners of the box body can be reduced. In the shallow box body having low side face portions, however, the projection size of the folded projecting portions (21) from the corners is intrinsically small, and it is unnecessary to dare to cut the folded projecting portions.
On the other hand, the package manufacturing process, may further comprise, in place of the steps (d) and (e):
(f) the step of folding the four sides of a rectangular cover member (30) to form a rectangular flat face portion (33) having substantially the same size as that of the bottom face portion (12), folded portions (31) folded from the four sides of the flat face portion (33), and triangular folded portions (34) protruding outward of the cover member at the intersections of the folded portions (31);
(g) the step of fitting the flat face portion (33) of the cover member (30) in the opening of the box body formed at the step (c), such that the folded portions (34) are inserted in the triangular regions (25) of the box body, to joint the inner faces of the side face portions (13, 14) and the outer faces of the folded portions (31); and
(h) the step of folding the upper portions of the side face portions (13, 14) outward with a predetermined width size (W1) to form flange portions (16, 17) and flange jointing portions (18) developed from the triangular regions (25), and developing the cover member (30).
At the step (a), on the other hand, a packaging material having a predetermined width and continuing in a band shape can be fed to form a plurality of box bodies continuing through a boundary region (iii) in the longitudinal direction of the packaging material.
However, the box bodies of the package can also be separately manufactured one by one.
In the continuous manufacture case, on the other hand, at the step (d), the upper portions of the second side face portions (14, 14) raised from the two widthwise sides of the band-shaped packaging material can also be folded to form the second flange portions (17, 17), and the spacing between the adjoining box bodies can also be enlarged to develop the boundary portion (iii) in a planar shape thereby to form the first flange portions (16, 16) and to develop the flange jointing portions (18) in a planar shape.
After the cover member was jointed to the box body, the boundary portion (iii) between the box bodies may be cut to separate them into individual box bodies.
Alternatively, after the cover member was jointed to the box body, the boundary portion between the box bodies may be cut at every other ones to separate an assembly having a plurality of box bodies continuing through the boundary portion. Moreover, the boundary portion (iii) connecting the plurality of box bodies may be perforated.
According to another aspect of the invention, there is provided an apparatus for manufacturing a package including a box body formed of a packaging material of a soft sheet and a cover member for closing the opening of the box body, comprising:
a packaging material feeding portion for letting off a band-shaped packaging material (35) of a soft sheet having a monolayer of a resin film or a multi-layer structure having a resin film, in a longitudinal direction;
a plurality of partitions (44) moving at a predetermined interval in the direction to feed the band-shaped packaging material, and a bottom positioning portion (45) interposed between the partitions;
a pusher (47) for pushing the band-shaped packaging material (35) onto the confronting inner faces of the partitions (44) and the bottom positioning portion (45), to form the packaging material (35) into a shape of letter xe2x80x9cCxe2x80x9d and to form a bottom face portion (12) in close contact with the bottom positioning portion (45) and first side face portions (13, 13) in close contact with the inner faces of the partitions (44);
folding means (48) for raising the two widthwise side portions of the band-shaped packaging material (35) to form second side face portions (14, 14) intersecting the first side face portions (13, 13) at a right angle thereby to form the packaging material (35) into a box body, and simultaneously to form triangular folded projecting portions (21) projecting from corner portions (20) between the first side face portions (13) and the second side face portions (14);
sealing means (51, 52) for jointing the inner faces of the folded projecting portions (21) along the corner portions (20) and while leaving only a predetermined size (W1) from the upper ends of the side face portions (13, 14), to form corner sealing portions (15), and for jointing the inner faces of the folded projecting portions (21) continuing to the corner sealing portions and while leaving non-jointed portions of triangular regions (25) using the corner portions (20) as their one side, to form jointed sealing portions (24);
developing means for folding the upper portions of the first and second side face portions (13, 14) outward with a predetermined width size (W1) to form first and second flange portions (16, 17) continuing to the upper ends of the first and second side face portions (13, 14), respectively, and for simultaneously developing the triangular regions (25) to form flange jointing portions (18) continuing planarly to the individual first and second flange portions (16, 17);
sealing means (61, 62) for jointing a cover member (30) to the upper faces of the flange portions (16, 17) and the flange jointing portions (18) developed in a planar shape; and
cutting means (63) for cutting the box bodies having the cover members jointed thereto, individually into one or a plurality.
This package manufacturing apparatus can further comprise: cutting means for cutting the folded projecting portions (21) while leaving narrow portions (22) including the corner sealing portions (15) and small triangular portions (23) along the jointed sealing portions (24).